Microbial contamination and growth in distillate fuels has been described for seventy years. The consequences have ranged from fouling of filters and injectors, to engine malfunction and damage, fuel gauge malfunctions and aggravated corrosion of engines, fuel tanks, equipment and facilities. The types of microbes present vary with the differences in fuel composition and differences in storage and use conditions. Anti-microbial strategies have traditionally included prevention by ‘good housekeeping’ and ‘fire-brigade’ applications of biocides when there are operational problems. Since 2002, first the aviation industry and later fuel suppliers and some militaries, have used simple on-site microbiological tests to monitor fuel and fuel systems and use the results to take remedial actions before operational problems occur. This paper will review our latest knowledge of microbially influenced corrosion and of the new anti-microbial strategies which are being successfully implemented to prevent it.